Inside the Boston Marathon Bombers Predawn Manhunt

Boston authorities caught up with the two men suspected of bombing the Boston Marathon late Thursday night and engaged in an hours-long firefight. One is dead, and the other is on the run. See the latest in the case of the Boston bombers.

Two towns just outside Boston’s city limits became a fiery war zone overnight as two fugitives suspected in Monday’s Boston Marathon bombings shot and killed a policeman, hijacked a car, and engaged in a roiling gun battle with police.

Addressing reporters at an early-morning news conference, Col. Timothy P. Alben, superintendent of the Massachusetts state police, said the drama began with reports of a robbery at approximately 10:20 p.m. at a convenience store in Cambridge, just 15 minutes from the site of the first blast.

The suspects then hijacked a Mercedes SUV at gunpoint, kidnapping its driver for 30 minutes before depositing their victim unharmed at a Cambridge gas station. They then drove to Watertown, a suburb five miles east of Cambridge, where they exchanged gunfire with a Massachusetts Bay Transportation Authority officer, wounding him, before again evading capture. As of Friday morning the officer remains in critical condition.

iPhone cameras captured the intense gunfight that turned the suburbs into a warzone.

But then the authorities, responding with an array of state and federal agencies, caught up with the suspects in Watertown shortly after midnight, commencing a prolongedgunfight that wound throughout the densely populated residential neighborhood. According to one Boston reporter,the authorities tracked the suspect using the stolen Mercedes’s built-in navigation system.

During the pursuit, Alben said, the suspects exchangedhundreds of roundsin a fiery gun battle with the officers, throwing several explosive devices from their car, including grenades and an “unwieldy bomb.” The action was captured by an army of tweeting beat reporters and iPhone-equipped locals.

Just after 1 a.m. ET, police were training their guns on a suspect lying facedown in the street.

During the exchange of fire, “Suspect No. 1” (photographed on Monday wearing a black baseball hat) was wounded by police gunfire and taken into custody. At 1:10 a.m., Beth Israel Hospital was notified of an incoming patient with multiple injuries; at 1:20 a.m., the suspect the arrived, suffering from traumatic arrest. Doctors tried to resuscitate him, but he was pronounced dead at 1:35 a.m. At an early-morning press conference, doctors described multiple injuries: bullet and shrapnel wounds and injuries consistent with an “explosive device.”

“You give the best care you can to every patient who comes to you regardless of who they may be,” the doctor said, in a briefing three hours after the suspect was declared dead, and added, “You have no idea who it is when you arrive and try to give them the best care you can when they arrive.”

“All we know is he arrived in arrest here,” the doctor said. “We don’t really know what happened.”

“Suspect No. 2,” the man photographed on Monday wearing a white baseball hat, was able to escape in the SUV—charging through a wall of Boston’s finest while they peppered the vehicle with bullets, according to an eyewitness—before fleeing the scene on foot. As of Friday morning, he remained at large.

And thanks to their convenience-store robbery, the authorities released a new, previously unseen photo of the second suspect, taken from the convenience store’s security camera.

The authorities described him as a light-skinned Caucasian male with brown, curly hair and dressed in a hooded, gray sweatshirt.

Asked to identify the suspects by name, both Alben and Boston Police Commissioner Ed Davis were mum, saying they were not prepared to talk about identifications—despite that two names were clearly floated to the 80,000-plus people listening in on Boston’s police scanner in the heat of the battle. Authorities later denied that those named were suspects.

In the coming hours, authorities said they plan to go door-to-door in Watertown until they find Suspect No. 2 or acknowledge that he has slipped their dragnet.

As the sun rises Friday morning, Boston residents unaware of the night’s events will find themselves without subway, commuter rail, or bus service, as the manhunt continues. Harvard University, Emerson College, Boston University, and MIT all canceled classes Friday due to security concerns.

In a briefing at around 4 a.m. ET, police recapped the night’s chaotic events.

At a predawn press conference, a Boston public-safety official warned residents of Watertown and the greater Boston area to stay indoors. Authorities announced that no cars will be allowed in or out of Watertown. “We’re asking businesses not to open. We’re asking people not to congregate outside. We’re asking people not to go to mass transit,” he said.

In the meantime, officials have a major cleanup to do. Residents are reporting bullet holes through their walls, unexploded ordnance in their streets, and a palpable sense of tension that comes with knowing a man suspected of mass murder is running freely, heavily armed and willing to kill again.

“We believe this to be a terrorist,’’ Davis told a crowd of bleary-eyed reporters just before 5 a.m. ET today. “We believe this to be a man here to kill people.”